Lumber Air Drying Fixture

I’ve been air-drying rough cut green lumber for many years with my shop-made fixture.

When wood is kiln dried, it is stacked and stickered with huge concrete weights on top. As the wood dries the concrete keeps the stack compressed to control twisting of the boards.

I designed this fixture, which works as follows. The main piece is the 10-foot long 6-inch square heavy wall tubing – unbendable for our purposes. Every two feet crossing the tubing is a heavy wall tubing to support the stack and hold the clamps.

Rather than use weights at the top, I made clamps with ready rod. Only one is shown in the photo. I cut 1 inch pieces of pipe large enough to go around the cross members and made that into a connector by drilling and tapping it for the ready-rod. I use 2×4 on edge for the clamp. Capacity of the fixture is limited only by the length of ready-rod used for the clamps.

As the stickered wood dries you simply tighten up the nuts on the ready rod clamps. Drying the wood from green to under 10%, you will probably tighten the nuts as much as 4 inches over about ten weeks.

One fixture is in the green house and the other is outside under a lean-to so I know both types of location works.

You can dry to under 10% and, because it is not dried in a hurry, you will get few split ends. There will be little to no twisting.

That is a great idea and a great design. i have passed up several trees i wanted to make into lumber, specifically because I have nowhere to dry it. Make one of these, and put it in my shed! I bet the materials would be reasonable, and a welding shop could fabricate most of it for me.

Ten weeks seems like a short time. What kind of weather do you have for a ten week drying time. That’s a nice simple design with only a little attention to tighten the nuts. Do you sell the lumber or use it for your business? Where do you get the trees? Do you cut the lumber your self? If not how much are you charged to cut the tree? I think you have solved the “Lumber cost Too much”. Nice design and thanks for sharing your creativity.It always easy when someone shows you how to do it!

Dominic – I’m not in business – just the family’s furniture maker. However, I’m a pretty avid hobbyist. I have used an alaska chainsaw mill when I had more energy and didn’t worry about yield. Here in the inerterior of British Columbia birch is abundant and there are numerous mini-mills for sourcing lumber. It is also cut to my specs to suit my projects. I pay about $1 bf for the lumber – the mill sources the log. Some day I’ll post the spalted birch kitchen I did a couple of years ago with local birch.

When I first looked at your picture, I thought to myself, “Doesn’t this guy know he needs to weight the lumber?” But I decided to read further and, WOW! what a terrific idea. I’m making a copy of this to show to my husband and the sawyer who brings his portable bandsaw mill to our property. We’ll have to check out what our local salvage yard gets for the metal, but it could probably work with an adequate I-beam as well. The only potential problem I could foresee is not getting all the cross-members perfectly level. How much weight (how many board feet) are you able to stack on this? What is the width— about 4’? What size stickers do you use?

One of our biggest problems is rodents when drying outside. We’ve tried 7/16” stickers (which most say is not adequate for air flow), but even that did not alleviate the rodent problem. We have tried an inside location but air flow was not sufficient. How do you solve that problem? Or aren’t you bothered with mice, etc. in Canada?

Sorry, for all the questions, but this is an exciting concept! We can learn SO much from our more-experienced LumberJocks! Thanks for the post!

I wish I knew this a couple years ago when I bought a bunch of maple, oak, and walnut, and dried it myself, I stickerd it ok and covered it but never thought to weight it down. So I ended up with a lot of twisted, cupped and warped lumber. I got a lot of good stuff too. I was lucky, but had way too much waste. Thanks for the info.

-- (You just have to please the man in the Mirror) Mike from Michigan -

This is a very cool idea. I like how it’s at waist level for easy loading/unloading. Does the steel stain the wood? I assume your threaded rod is galvanized?

I plan to take the mill to the log once i start milling (coupe felling or windthrown NZ beech) and because I’m practicing low impact forestry, my plan was to set up an air drying platform next to the mill site in the forest. The thought was to let it air dry sufficiently on location so that extraction will be easier because of the lighter weight.

I can see using this design and building a portable version that I can hand carry into the forest and then remove when I remove the wood. Maybe out of aluminium or even wood.

Thanks for all the comments. Drying time will be affected by local conditions and board thickness so an 8/4 stack will take longer than 4/4 stack. An I-beam will work just as well – I just happened to have the tubing.I did forget to mention that I put stickers between the first row and the supports. Also the stickers should be directly above the supports in your stack because that is where the clamping pressure is. I’m not sure there is a science about the thickness of the sticker – the key is air movement either by fan or by wind. We live between a lake and a mountain so have a breeze nearly every day and I have a fan with reversed motor in the green house pulling air through the stack. If you do this, you will find it is like making your own wine – just stay ahead of the demand.